Multiple Database Support

Work is underway on a patch for #1142, which will add support for multiple database connections. This page documents my current plan and progress towards a fully working patch.

The plan

• Add a new settings variable, DATABASES. DATABASES is a dict of named database connection parameter sets. In each set, the keys are the same as the standard database connection settings variables.

  DATABASES = { 
      'a': { 'DATABASE_ENGINE': 'sqlite3',
             'DATABASE_NAME': '/tmp/dba.db'
      },
      'b': { 'DATABASE_ENGINE': 'sqlite3',
             'DATABASE_NAME': '/tmp/dbb.db'
      }}
  

• Add db_connection to Meta. This allows model classes to specify which connection they should use.

  class Artist(models.Model):
      name = models.CharField(maxlength=100)
      alive = models.BooleanField(default=True)
  
      def __str__(self):
          return self.name
  
      class Meta:
          db_connection = 'a'
          
  class Widget(models.Model):
      code = models.CharField(maxlength=10, unique=True)
      weight = models.IntegerField()
  
      def __str__(self):
          return self.code
      
      class Meta:
          db_connection = 'b'